This invention relates to a soil filtration and water drainage device that permits the free flow of water therethrough, but prohibits surrounding soil from ingressing therein and moving therethrough. The device is relatively light weight, inexpensive, non-biodegradable, and substantially deformable to adapt to any desired configuration with respect to the surrounding soil or other material.
Perhaps the simplest of soil drainage devices and systems is simply the placement of sand, gravel or rocks in selected locations in the soil. Such systems permit the flow of water therethrough, but gradually become clogged with soil, which inhibits the flow of water. Although such systems are usually relatively inexpensive and readily conform to the surrounding soil and other material, such systems are very heavy.
Another type of simple soil drainage system is the provision of a series of perforated pipes at selected locations within the soil to carry away water. Such systems are usually used in combination with surrounding sand, gravel or stone to minimize the flow of soil into the pipes, which would eventually congest the flow of water into and through the pipes. Such systems are moderately expensive and moderately adapt to the surrounding soil and other materials and are moderately effective. Such systems are also relatively heavy.
Yet another soil drainage system utilizes one or two sheets of porous geotextile fabric covering an open structural material through which water can flow. The structural material usually includes raised plastic cones or stiff plastic threads and offers a relatively thin drainage profile. Such sheets are usually flexible in only one plane and are especially adapted to be disposed adjacent to concrete foundation walls. They prevent the surrounding soil from compressing directly against the foundation wall and permit water to flow within or between the structural material. This system is reletively expensive to manufacture and install.
A more recent soil drainage system incorporates a drainage panel or board having a sheet of geotextile filter fabric along one surface thereof. The board is fashioned of several small polystyrene beads bonded together and encapsulated by an asphalt adhesive. The geotextile filter fabric permits water, but not soil, to pass therethrough. The board is oriented such that the geotextile filter fabric faces the surrounding soil, and water, but not soil, is permitted to pass through the geotextile filter fabric and through the board. The board is rigid, water resistant, and combustible. Moreover, the board is relatively expensive, and not readily adaptable to the shape of the surrounding soil and other materials.